1. Field of the Invention
The present invention relates to a disc cartridge which rotatably accommodates in a cartridge housing a disc-shaped storage media such as an optical disc, a magnetic disc, a magneto-optical disc and the like capable of recording (writing) and/or reproducing (reading) an information signal such as audio information, video information or computer data information and the like.
2. Description of the Related Art
In recent years, as a disc cartridge which rotatably accommodates in a disc cartridge housing a disc-shaped storage medium such as a magneto-optical disc or the like, for example, what is shown in FIG. 16 has been generally known. A cartridge disc 1 is one so called an MD (mini-disc) with a disc-shaped storage medium of 64 mm in diameter being built therein. Of the MD1, there are a reproduction-only MD and a recording and/or reproducing MD. The recording and/or reproducing MD is comprised of a cartridge housing 2 and a magneto-optical disc 3 while the reproducing-only MD is comprised of a cartridge housing and an optical disc.
FIG. 16 is a perspective view of the MD1 seen from a reverse side and the cartridge housing 2 thereof comprises upper and lower halves 2a and 2b which are superposed each other and the magneto-optical disc 3 is rotatably accommodated in a disk accommodation room which is formed in both the upper and lower halves 2a and 2b. The upper and lower halves 2a and 2b are made square shaped when seen from the front and nearly at the central portion of its one side are respectively provided opening windows 4 penetrating in an up to down direction. These opening windows 4 are extended to nearly a central portion of the cartridge housing 2 and are made capable of being opened and closed by a slide shutter 5.
The slide shutter 5, having a cross-sectionally U-letter shape, comprises an upper shutter tab 5a for closing the opening window 4 provided in the upper half 2a, a lower shutter piece for closing the opening window provided in the lower half 2b and a side piece 5b for connecting both the shutter pieces. Then, the cartridge housing 2 is provided with a lock mechanism for locking the slide shutter 5 when the opening window 4 is in a state of being closed. Also, nearly at a central portion of the lower half 2b is provided a central hole 6 for exposing a hub plate 3a of the magneto-optical disk 3, with the central hole 6 being always opened.
The MD1 having such an arrangement is, with the lower half 2b in a state of facing downward, inserted into a cartridge inserting mouth of a disc recording and/or reproducing apparatus from an arrow mark direction X. Consequently, the locking by the rock mechanism is released by a manipulating pin provided in the disc recording and/or reproducing apparatus and the manipulating pin as it is, slides the slide shutter 5 in an opposite direction to the arrow mark direction X. As a result, the opening windows 4 are opened, thereby making it possible to insert an optical head of an optical pick-up device in the opening windows 4.
However, since the conventional disc cartridge has been constituted such that the cross-section U-letter shaped slide shutter fits in the outside of the cartridge housing as well as the shutter piece 5a are respectively slid on the outsides of the upper and lower halves 2a and 2b to open and close the opening windows 4, clearances tend to be easily in place due to curling of the free end side of the shutter pieces 5a, thereby incurring a problem that minute trash and dust tend to easily enter into the cartridge housing 2 from the clearances. In this case, with an information storage medium with a large information capacity, the influence of the minute trash and the dust can not be negligible and when it is impossible to prevent the intrusion of the minute trash or the dust, there is a fear that the information storage surface of the disc-shaped storage medium is damaged by the minute trash or the dust. When the information storage surface is damaged, it becomes impossible to read and write a normal information signal.
With the conventional disc cartridge, since the slide shutter 5 is in place which is easily touched by the hand of a user, there is a fear that the user accidentally opens the slide shutter 5. When the user accidentally opens the slide shutter 5 in this manner, the influence of the trash and dust becomes increasingly larger with the higher density of the information record and hence, there have been problems that a loss of and the damage to an information record are feared to occur by the existence of the trash and dust.
The present invention is implemented in view of such conventional problems and its object is to provide a disc cartridge which has such an arrangement to prevent erroneous opening and closing operations by making it difficult for the hand of a user to touch it as well as for minute trash and dust to intrude therein, thereby making it possible to avoid the loss of the information record caused by the minute trash and dust.
According to a first aspect of the present invention, there is provided a disc cartridge for accommodating a disc-shaped storage medium in which at least one of recording or reproducing of an information signal is carried out by a head unit of a pick-up device, which comprises a pair of halves superposed upon each other for forming a disc accommodation room for rotatably accommodating the disc-shaped storage medium, and a shutter member capable of opening and closing an opening window which is provided in at least one half out of a pair of the halves and into which a head unit can be inserted, wherein the shutter member is movably supported between the pair of the halves.
According to a second aspect of the present invention, there is provided a disc cartridge, wherein a shutter supporting body for supporting a free end side of the shutter member is provided between the pair of halves.
According to a third aspect of the present invention, there is provided a disc cartridge, wherein the shutter supporting body is an inner case which forms a disc accommodation room between the same and the half without the opening window, and the inner case is provided with an opening portion corresponding to the opening window of the half having the opening window.
According to a fourth aspect of the present invention, there is provided a disc cartridge, wherein the shutter member is provided with an overlapping portion which is overlapped on a peripheral portion of at least one of the opening window or opening portion.
According to a fifth aspect of the present invention, there is provided a disc cartridge, wherein the shutter member is provided with a convex portion which comes in contact with either one of the shutter supporting body or the half with the opening window as urges the shutter member against the other one of the shutter supporting body or the half with the opening portion by a reaction force from the contact portion.
According to a sixth aspect of the present invention, there is provided a disc cartridge, wherein a lock mechanism for locking the shutter member at a position where the opening window is closed is provided.
In the disc cartridge of the first aspect arranged as mentioned above, since the shutter member is supported between the pair of the halves, the shutter member is made to have such an arrangement which makes it difficult for the hand of a user to touch the shutter member to prevent erroneous opening and closing operations as well as for minute trash and dust to intrude so that a loss of information records due to the minute trash and dust can be prevented.
In the disc cartridge of the second aspect, by supporting a free end side of the shutter member with the shutter supporting body provided in the half with no opening window, the free end side is prevented from flexing and the malfunction of the shutter member to come in touch with the disc-shaped storage medium can be avoided.
In the disc cartridge of the third aspect, the half with no opening window and the inner case form a sealed disc accommodation room to prevent the trash and dust from intruding and the head unit can be brought to nearly the disc-shaped storage medium by the opening portion of the inner case.
In the disc cartridge of the fourth aspect, by shielding a clearance along the whole periphery of the opening window with an overlapping portion of the shutter member, the trash and dust can be prevented from intruding into a cartridge housing as well as the disc-shaped storage medium can be prevented from being attached with the trash and the like as well as being damaged by the trash and the like.
In the disc cartridge of the fifth aspect, by pressing the shutter member with the convex portion provided in the shutter member against the opening window or the opening portion, the clearance into which the trash and dust intrude is made smaller, thereby making it possible to prevent the disc-shaped storage medium from being attached with the trash and the like as well as from being damaged by the trash and the like.
Also, in the disc cartridge of the sixth aspect, by locking the shutter member at a position where the opening window is closed, the shutter member can be prevented from being freely opened as well as from erroneous operations of opening and closing.